Fastening overlying sheets by partially piercing and deforming sections of the sheets is a fairly common practice generally referred to as spot clinching. This method has been successfully employed for many years since it eliminates the need for a separate fastener and is adequate for sheet metal joints used in joining ducts or the like. The technique is fairly simple in that it only requires that a section of the sheets be punched or pierced and subsequently deformed to lock the sheets together. Normally this has been achieved in a two-punch system wherein the sheets are pierced at the first step and the pierced section swaged at the second step. Where piercing and swaging have been accomplished by a single punch, the punch and/or die is moved in a sequence of steps to complete the operation. This involves the use of a linkage system to provide the different punching motions and to strip the pierced section from the die.